Dynamic co-culture of endothelial and smooth muscle cells as a platform for pathophysiological investigations of vascular calcifications

Vascular calcification (VC) is a cardiovascular condition where calcium salt deposits occur within the vessel wall by vascular smooth muscle cells (VSMCs). In vitro models used for investigating vascular calcification typically involve VSMC monocultures under static conditions. However, given the significant role that endothelial cells (ECs) and VSMCs play in vascular function, both in physiological and pathological conditions, the aim of the current study was to create a dynamic co-culture of ECs and VSMCs that could better replicate the in vivo vascular microenvironment. The presented work utilized a double-flow bioreactor to facilitate cellular interactions and emulate blood flow dynamics. To induce VSMC calcification, the cells were placed in a calcification medium composed of high glucose DMEM supplemented with 1.9 mM NaH 2 PO 4 /Na 2 HPO 4 (1:1) for 7 days. The study assessed calcification, cell viability, inflammation, and molecular markers (SIRT-1, mTOR-1, TGFβ1, and Elastin IV). Results revealed that the dynamic model could replicate VSMC calcification and an inflammatory environment. Additionally, the regulation of effectors responsible for VSMC calcified phenotypic displayed an opposing trend to that seen in static monoculture, highlighting the significance of ECs-VSMCs communication in controlling cell behavior. Therefore, this model provided information that was not obtainable with standard cell monoculture, demonstrating its usefulness in exploring the pathophysiologic mechanisms behind vascular calcification because of its enhanced ability to imitate human vascular tissue